Electric Motor

ABSTRACT

A rotary and linear motion device includes a magnetic stator assembly, opposed electromagnetic actuators, and a linear-to-rotary converter (e.g., cam). Each electromagnetic actuator includes a coil that is configured to reciprocate relative to the magnetic stator assembly or to linearly translate in a common direction relative to the magnetic stator assembly. The electromagnetic actuators are coupled to the linear-to-rotary converter and upon reciprocation or linear translation, drive the linear-to-rotary converter in rotary or linear motion. The device may be located inside a wheel, which may be part of a vehicle. If part of a wheel of a vehicle, the device can be used to provide propulsion, steering, braking, and suspension for the vehicle.

RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.12/590,495, filed Nov. 9, 2009.

The entire teachings of the above application(s) are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

A motor in a vehicle is typically located in a central part of thevehicle, such as, for example, in front of the passenger compartment ofthe vehicle. Centrally-located motors drive the wheels of the vehiclevia drive shafts, universal joints, and other components. Such motorsmay, for example, be fuel or electrically powered. Motors may also belocated at or even in the wheels of a vehicle. These motors are known ashub motors and are typically electrically powered. A vehicle with fourwheels may have, for example, four hub motors, one motor within eachwheel.

SUMMARY OF THE INVENTION

With greater interest in electrically-powered vehicles, including hybridvehicles, there is more interest in hub motors. However, hub motorssuitable for vehicles have not previously been made available. A typicalproblem associated with a hub motor is that the primary mass of themotor is not suspended by the vehicle's suspension components and,therefore, contributes to the un-sprung mass of the vehicle. Byproviding a reciprocating coil motor to drive a wheel about a hub, theheavier components of the motor can be supported in the sprung mass ofthe vehicle, resulting in better ride and handling. In fact, the coilitself may serve as a component of the suspension.

A rotary device may include, a magnetic stator assembly, opposedelectromagnetic actuators, and a linear-to-rotary converter. Eachelectromagnetic actuator includes a reciprocating coil that reciprocatesrelative to the magnetic stator assembly. The electromagnetic actuatorsare coupled to the linear-to-rotary converter and, upon reciprocation,drive the linear-to-rotary converter in rotary motion. Thelinear-to-rotary converter may be, for example, a cam, Scotch yolk,crank, or other mechanical device for converting linear motion intorotary motion. The coils may also linearly translate in a commondirection relative to the magnetic stator assembly to drive thelinear-to-rotary converter in linear motion. The linear motion may occurwith or without the rotary motion.

A vehicle may include a chassis, magnetic stator assembly coupled to thechassis, cam suspended on the chassis, and opposed coils suspended onthe chassis. The coils reciprocate in opposition relative to themagnetic stator assembly and drive the cam in rotary motion through camfollowers. A wheel of the vehicle is coupled to the cam and driven inrotary motion by the cam about a rotary bearing.

The magnetic stator assembly may include a single magnetic stator thatis shared by the coils or may include multiple magnetic stators, eachmagnetic stator corresponding to a coil. A magnetic stator may include asingle magnet or multiple magnets, and the coils may surround the singleor multiple magnets, in which case the multiple magnets are innermagnets. The stator may further include multiple additional magnetsarranged parallel to the first magnets and arranged outside of thecoils, in which case the multiple additional magnets are outer magnets.In such a configuration, followers may be coupled to the coils atlocations not covered by the outer magnets. For example, the coils maybe rectangle-shaped, and four outer magnet assemblies may be arrangedoutside of the coils and along the four sides of the coils, but notcovering the corners of the coils. The followers may then be connectedto the corners of the coils, through intermediate structures, such as,for example, housings that surround the coils. The rectangle-shapedcoils may be manufactured by stamping or etching and bending a pluralityof coil segments, such as U-shaped segments, and assembling the coilsegments into a coil.

In configurations including a cam, the cam may be located on one side ofa disc, where the magnetic stator assembly is arranged parallel with theplane of the disc. Further, the electromagnetic actuators may be coupledto the cam using followers, and rotary motion of the cam may causerotary motion of the disc, which in turn rotates any wheel coupled tothe disc. The opposed coils may be arranged to reciprocate 180 degreesout of phase with each other to cancel each other's vibrations. The camof the device may include an inner surface and an outer surface, andeach of the coils may be coupled to the cam using a pair of followers,where a first of each pair of followers interfaces the inner surface anda second of each pair of followers interfaces the outer surface. In oneconfiguration, the cam may include a protrusion with inner and outersurfaces, where the inner surface faces inward and the outer surfacefaces outward. Alternatively, the cam may include a groove with innerand outer surfaces, where the inner surface faces outward and outersurface faces inward. In such a configuration, each pair of camfollowers are arranged inside the groove. The cam may take a variety offorms. For example, the cam may include an even number of lobes, each ofwhich may be in the form of a portion of an Archimedes spiral.

The device may also include a mount coupled to the magnetic statorassembly. The mount may be used to couple the device to the chassis of avehicle, for example. The device may include a support structure coupledto the mount and magnetic stator assembly through a plurality of shaftscoupled to the support structure and arranged parallel to the long axisof the magnetic stator assembly, where the coils reciprocate along themagnetic stator assembly by sliding along the shafts using linearbearings or similar components. The support structure may also becoupled to the cam and disc using a rotary bearing. In applicationsinvolving a vehicle, the support structure may be coupled to the chassisof the vehicle and the disc may be arranged inside a wheel of thevehicle, where rotational movement of the disc causes rotationalmovement of the wheel.

In addition to driving the linear-to-rotary converter in rotary orlinear motion, the electromagnetic actuators may act as generators bydrawing current from the coils as the linear-to-rotary converter rotatesor translates. When acting as generators, they absorb energy from therotational or linear movement of the linear-to-rotary converter toreduce the rotational or linear movement of the linear-to-rotaryconverter, for example, in regenerative braking or active regenerativesuspension.

The device may also include first and second cams, where the first camis located on one side of a disc and the second cam is located on theopposite side of the disc. Such configurations may also include a secondmagnetic stator assembly arranged parallel to the first magnetic statorassembly and on the opposite side of the disc. Those configurations mayalso include additional electromagnetic actuators that includerespective additional coils, where the additional coils are coupled tothe second cam using additional followers and that reciprocate inopposite directions along the long axis of the second magnetic statorassembly. The reciprocation of the additional coils contributes to therotational movement of the disc. In devices that include two cams, thefirst and second cams may be rotationally offset from each other by, forexample, forty-five degrees.

The device may also include liquid jets that are arranged to sprayliquid onto the coils as they pass by the jets in order to cool thecoils. The jets may be mounted to the magnetic stator assembly and mayspray liquid onto the coils through openings in magnets of the magneticstator assembly. In addition, the sprayed liquid may be converted to gasand vented from the device.

In applications that involve a vehicle, for example, with one or morewheels, the magnetic stator assembly, cam, rotary bearing, supportstructure, shafts, and coils may all be located within the boundaries ofa wheel. In such applications, the magnetic stator assembly may beoriented in a vertical direction with respect to the chassis of thevehicle, where translational movement of the wheel in the verticaldirection acts as a suspension for the vehicle. With such a suspension,the wheel, cam, and coils are un-sprung mass, and the chassis, magneticstator assembly, support structure, and shafts are sprung mass.

The device may also include an electrical unit that is suspended on thechassis and used to deliver electricity to the coils. This configurationmay also include a fiber-optic cable that runs between the electricalunit and the vehicle and used to control the electrical unit. In someconfigurations, the electrical unit may include a bidirectional powersupply connecting the coils and a battery, where the battery may bemounted inside the wheel of the vehicle or to the chassis of thevehicle. Further, the electrical unit may be configured to provide anelectrical component to the coils to drive the coils in the samedirection, thereby creating a vertical translational movement of thewheel. In addition, any translational movement of the wheel, caused bythe device or not, may be sensed by the electrical unit. In someconfigurations, the electrical unit may be configured to absorb energyfrom the translational movement of the wheel by causing the coils to actas electrical generators and dampers.

The device may include a wheel support structure and a fluid damper tocouple the support structure to the chassis of the vehicle. The supportstructure then may serve as a primary suspension, perhaps sliding alongshafts coupling the support structure and the mount, where the slidingis dampened by the fluid damper. The fluid damper may be a pneumaticsuspension between the support structure and the chassis and may includea piston with opposed pneumatic pressures applied to opposite faces ofthe piston. Pressure may be adjusted to vary stiffness of thesuspension. The pneumatic suspension may then provide lower-frequencydamping as the coils provide higher-frequency damping. Furtherconfigurations may including a plurality of flexures that are used todeliver electricity to the coils, where a first set of flexures isconnected between the chassis and the support structure, and a secondset of flexures is connected between the support structure and thecoils.

Applications involving a vehicle may include two rotary devices, whereeach device includes a magnetic stator assembly, opposed coils, cam,rotary bearing, and wheel. In these configurations, the rotary devicesmay both rotate in the same direction, thereby creating propulsion forthe vehicle. The wheels of the rotary devices may also rotate atdifferential rates or directions, thereby causing the rotary devices,and wheels, to turn with respect to the vehicle. Such a vehicle may besteered while in motion by differing the rotational speeds of thewheels. The vehicle may also move in a vertical direction by causing thewheels to move in the same vertical direction, perhaps with sufficientforce to cause the vehicle to jump. The two devices may also tilt thewheels by moving the two wheels in opposite vertical directions.Further, the devices may rapidly raise and shake one of the wheels inthe vertical direction to remove liquid from the surface of the shakingwheel. Some vehicular configurations may include four corners with tworotary devices at each corner. In these configurations, each pair mayrotate about a respective vertical axis. The four pairs of rotarydevices may turn their respective wheels to turn the vehicle or evenrotate the vehicle around its center. The four pairs of rotary devicesmay also turn their respective wheels inward to park the vehicle.

An electric generator device includes a rotary-to-linear converter, amagnetic stator assembly, and opposed coils. Each coil is arranged toreciprocate relative to the magnetic stator assembly and is coupled tothe rotary-to-linear converter, which may be, for example, a cam, Scotchyolk, crank, or other mechanical device for converting rotary motioninto linear motion. Upon rotation, the rotary-to-linear converter drivesthe coils in opposed reciprocation, resulting in electric currentflowing though the coils, which may then be harvested by drawing currentfrom the coils. The coils may linearly translate in a common direction,along with the converter, relative to the magnetic stator assembly,which also results in electric current flowing though the coils. Thelinear motion may occur with or without the rotary motion.

Instead of being made from one continuous piece of material, an electriccoil may include multiple flat coil segments stacked together andelectrically coupled in series, where each coil segment is rotated withrespect to the coil segment it follows in the stack. For example, eachcoil segment may be U-shaped and may be rotated 270 degrees with respectto the coil segment it follows in the stack of coil segments. A methodof manufacturing such an electric coil includes fabricating multipleflat coil segments, stacking together and electrically coupling themultiple coil segments in series where each coil segment is rotated withrespect to the coil segment it follows, and fastening the coil segmentstogether to form the electric coil.

The coil segments may be inexpensively formed by stamping or etching andbending the coil segments from a flat sheet of metal, for example. Allsides of a coil segment may be equal in length or, alternatively,adjacent sides of a coil segment may be different lengths while oppositesides of the coil segment may be equal lengths. The coil may furtherinclude electrically-insulating material on portions of the coilsegments. In a stack of coils segments, for example, all surfaces of thecoil segments may be coated with an electrically-insulating layer ofmaterial except for the top surface of the finishing end of a lower coilsegment in the stack and the bottom surface of the starting end of animmediately upper coil segment in the stack. The segments may befastened together using bolts, for example, that may be inserted throughthe corners of the coil segments. A layer of electrically-insulatingmaterial may also cover the bolts. When assembled,electrically-insulating spacers may be placed in any gaps between thecoil segments.

A tunable pneumatic suspension may include a piston and opposed chambersapplying respective opposed pneumatic pressures to opposite faces of thepiston. The suspension may also include a pneumatic controller thatindependently controls the pneumatic pressures in the chambers. Thepressures of the chambers may be adjusted to change the relativepositions of the piston and the chambers by differing the pressures.Additionally, the pressures of the chambers may be adjusted to changethe stiffness of the suspension by adding or removing equal pressures toor from the chambers. Adding equal pressure to both chambers increasesthe stiffness of the suspension, and removing equal pressures from bothchambers decreases the stiffness of the suspension. If the suspension ispart of a vehicle, changing the relative positions of the piston and thechambers can change the ride height of the vehicle, and changing thestiffness of the suspension can change the stiffness of the vehicle'sride.

This application relates to U.S. patent application titled “ELECTRICGENERATOR” by inventor Ian W. Hunter (Attorney Docket No.4489.1002-000), U.S. patent application titled “ELECTRIC COIL AND METHODOF MANUFACTURE” by inventors Ian W. Hunter and Timothy A. Fofonoff(Attorney Docket No. 4489.1003-000), and U.S. patent application titled“TUNABLE PNEUMATIC SUSPENSION” by inventor Ian W. Hunter (AttorneyDocket No. 4489.1004-000). These applications are being filedconcurrently with the present application, and the contents of theseapplications are incorporated herein by reference in their entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIGS. 1A and 1B illustrate example rotary devices.

FIG. 1C illustrates an example magnetic stator assembly.

FIGS. 1D-1F illustrate cross-sections of example rotary devices.

FIGS. 2A-2C illustrate components of an example rotary device in action.

FIG. 2D illustrates an example shape of a cam.

FIGS. 2E-2H illustrate an example rotary device in action and coupled toa wheel.

FIGS. 3A and 3B illustrate an example rotary device with an additionalcam and magnetic stator components.

FIG. 4A illustrates a mount attached to the magnetic stator assembly ofan example rotary device.

FIG. 4B illustrates a simplified cross-section of an example rotarydevice attached to the chassis of a vehicle.

FIGS. 5A-5D illustrate a support structure coupling a magnetic statorassembly and mount of an example rotary device with electromagneticactuators and coils of the device through a plurality of shafts.

FIG. 6A illustrates a rotary bearing coupling a support structure of anexample rotary device with a cam of the device.

FIG. 6B illustrates a wheel structure coupling a cam of an examplerotary device with a wheel of a vehicle.

FIG. 7 illustrates a horizontal cross-section of an example rotarydevice.

FIG. 8 illustrates a horizontal cross-section of an example rotarydevice from a top-down view.

FIG. 9 illustrates an inner structure of a magnetic stator assembly ofan example rotary device.

FIG. 10 illustrates a horizontal cross-section of an example rotarydevice.

FIG. 11 illustrates a horizontal cross-section of an example rotarydevice.

FIG. 12A illustrates a vertical cross-section of an example rotarydevice showing how a support structure of an example rotary device maybe arranged.

FIGS. 12B-12D illustrate an example tunable pneumatic suspension.

FIGS. 13A and 13B illustrate an example rotary device at differentvertical positions.

FIGS. 14A-14C illustrate the construction of an example coil of anelectromagnetic actuator.

FIG. 15 illustrates a wheel that includes an example rotary device.

FIGS. 16A and 16B illustrate different views of an example rotarydevice.

FIGS. 16C and 16D illustrate two rotationally offset cams.

FIG. 16E illustrates an example shape of a cam.

FIGS. 17A and 17B illustrate a disc of an example rotary device coupledto a rim of a wheel.

FIG. 18 illustrates two support structures coupling respective magneticstator assemblies with electromagnetic actuators through a plurality ofshafts and fluid dampers.

FIGS. 19A-19C illustrate an example arrangement of magnetic stators.

FIGS. 20A-20G illustrate the construction of an example coil of anelectromagnetic actuator.

FIGS. 21A and 21B illustrate a side view and a top view of two rotarydevices with respective wheels.

FIGS. 22A-22C illustrate various different rotations of the wheels.

FIGS. 23A and 23B illustrate vertical movement of the wheels.

FIGS. 24A-24F illustrate a top view of a vehicle having four pairs ofrotary devices with respective wheels.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

FIG. 1A shows an example rotary device 100 inside a wheel. The deviceincludes a magnetic stator assembly 120, opposed electromagneticactuators 110 a, 110 b, and a linear-to-rotary converter (e.g., cam)105. The device may be attached to the chassis of a vehicle, forexample, at a point on the far side of the wheel (not shown). The rotarydevice depicted inside the wheel may be attached to the wheel via thecam 105 using a circular plate, for example, which has been removed toshow the inside of the wheel. Such a plate may be attached to both therim of the wheel and the cam 105 using fasteners, such as bolts. Thewheel and cam support plate rotate relative to a hub 145 about a bearing150. It is important to note that the cam 105 is shown as an oval shape,but may take other forms, such as, for example, a cam having multiplelobes.

FIG. 1B shows the example rotary device 100 from the side of the wheel140 and with the tire of the wheel 140, and some other components,removed. The core of the rotary device includes the cam 105, two opposedelectromagnetic actuators 110 a, 110 b, and magnetic stator assembly120. The electromagnetic actuators 110 a, 110 b each include a coil 115a, 115 b that is arranged to reciprocate relative to the magnetic statorassembly 120. One electromagnetic actuator 110 a is shown having ahousing 155 a surrounding its coil 115 a and the other electromagneticactuator 110 b is shown with its housing removed to show its coil 115 b.

The magnetic stator assembly 120 depicted in FIG. 1B is orientedvertically and may include a plurality of magnetic stators 125 a, 125 b.Each of the magnetic stators 125 a, 125 b may include a single magnet ormultiple magnets. As current is applied to the coils 115 a, 115 b of theelectromagnetic actuators 110 a, 110 b (e.g., alternating current), theactuators 110 a, 110 b are forced to reciprocate vertically along themagnetic stator assembly 120 due to the resulting electromagneticforces. As known in the art, when a coil carrying an electrical currentis placed in a magnetic field, each of the moving charges of the currentexperiences what is known as the Lorentz force, and together they createa force on the coil. As depicted, the rotary device 100 may include aplurality of shafts 130 a, 130 b, coupled to a bearing support structure165. The electromagnetic actuators 110 a, 110 b may slide along theshafts using, for example, linear bearings. Other bearings that may beused include air bearings, silicon nitride bearings, graphite bearings,and linear recirculating ball bearings. Attached to each electromagneticactuator 110 a, 110 b may be a pair of followers 135 a-d used tointerface with the cam 105. To reduce friction, the followers 135 a-dmay spin to roll over the surfaces of the cam 105. The followers 135 a-dmay be attached to the electromagnetic actuators 110 a, 110 b via, forexample, the actuators' housings. As the electromagnetic actuators 110a, 110 b reciprocate, the force exerted by the followers 135 a-d on thecam 105 drives the cam 105 in rotary motion.

FIG. 1C illustrates an example magnetic stator assembly 120 with twomagnetic stators 125 a, 125 b. The magnetic stators 125 a, 125 b eachinclude multiple magnets. For example, magnetic stator 125 a includes,on one surface of the stator 125 a, eight magnets 160 a-h.

FIGS. 1D-1F illustrate simplified cross-sections of example rotarydevices. The device of FIG. 1D is within a wheel 140 of a vehicle andincludes a hub (or mount) 145 coupled to a magnetic stator assembly 120having two magnetic stators 125 a, 125 b. Also shown are twoelectromagnetic actuators (including coils) 110 a, 110 b thatreciprocate relative to the magnetic stator assembly 120 along shafts130 a, 130 b (shown as dashed lines). The shafts 130 a, 130 b arecoupled to a bearing support structure 165, keep the components of thedevice in vertical alignment, and prevent the wheel 140 from falling offof the device. A cam plate 170 coupled to the wheel 140 is rotablycoupled to the bearing support 165 through a bearing 150. Affixed to thecam plate 170 is a cam 105 used to drive the plate 170 and, thus, thewheel 140 in rotary motion. The cam 105 is driven by the reciprocationof the electromagnetic actuators 110 a, 110 b using followers 135 a-dthat are coupled to the electromagnetic actuators 110 a, 110 b and thatinterface with the cam 105. Also included in the example device is afluid damper 175 a coupling the bearing support 165 and the mount 145.The fluid damper 175 a suspends the mount 145 above the ground and mayallow for some movement between the bearing support 165 and the mount145, depending on the amount of resistance of the damper. For example,if the damper is a pneumatic damper, higher gas pressures inside thechambers of the damper allow for less movement than lower air pressures.

FIG. 1E illustrates that in the absence of the fluid damper 175 a, theelectromagnetic forces caused by the electromagnetic actuators 110 a,110 b and magnetic stators 125 a, 125 b may suspend the mount 145 abovethe ground. If, however, electrical current is removed from theelectromagnetic actuators 110 a, 110 b, the associated electromagneticforces will also be removed and the mount 145 may drop toward theground, along with the magnetic stator assembly 120 and vehicle chassis,as illustrated in FIG. 1F.

FIGS. 2A-2C illustrate components of the rotary device 100 in action,including the rotary device's electromagnetic actuators 110 a, 110 b(with associated coils 115 a, 115 b and followers 135 a-d) and cam 105moving relative to the magnetic stator assembly 120 (includingassociated magnetic stators 125 a, 125 b). The housings by which thefollowers are attached to the coils are not shown in these figures. Asillustrated by FIGS. 2A-2C, the reciprocal movement of the coils 115 a,115 b in opposition drives the cam 105 to rotate, which, in turn, maycause a wheel attached to the cam 105 to rotate. The coils 115 a, 115 bare shown in FIG. 2A as being at almost their furthest distance apart.FIG. 2B shows that as the coils 115 a, 115 b move closer to each other,the coils 115 a, 115 b drive the cam 105 to rotate in a clockwisedirection, thereby causing any attached wheel to also rotate clockwise.In the example device, the force exerted on the cam 105 is caused by theouter followers 135 a, 135 c squeezing-in on the cam 105. FIG. 2C showsthat the coils 115 a, 115 b are yet closer together causing furtherclockwise movement of the cam 105.

After the coils 115 a, 115 b have reached their closest distancetogether and the cam 105, in this case, has rotated ninety degrees, thecoils 115 a, 115 b begin to move away from each other and drive the cam105 to continue to rotate clockwise. As the coils 115 a, 115 b move awayfrom each other, the inner followers 135 b, 135 d exert force on the cam105 by pushing outward on the cam 105. Again, it is important to notethat the cam 105 is shown in the figures as an oval shape, but the cam105 may be shaped in a more complex pattern, such as, for example, ashape having an even number of lobes, as illustrated in FIG. 2D. Thesides of each lobe may be shaped in the form of a sine wave or a portionof an Archimedes spiral, for example. The number of lobes determines howmany cycles the coils must complete to cause the cam to rotate fullcircle. A cam with two lobes will rotate full circle upon two coilcycles. A cam with four lobes will rotate full circle upon four coilcycles. Additionally, more lobes in a cam creates a higher amount oftorque. In addition to driving the cam in rotational motion, theelectromagnetic actuators may act as generators by drawing current fromthe coils as the cam rotates. This also has the effect of reducing therotational movement of the cam when energy is absorbed from therotational movement of the cam. In an application of the device in avehicle, drawing current from the coils may act as a regenerativebraking mechanism for the vehicle. Because the devices may act asgenerators, rotation of the wheel caused by an outside force mayrecharge the batteries of a vehicle. For example, the vehicle may bepositioned so that at least one of its wheels is placed on a rechargingdevice that causes the wheel to rotate. Such a recharging device may besimilar to a dynamometer, which may be placed on or in a floor. Butwhile a vehicle causes a dynamometer to rotate, it is the rotation ofthe recharging device that causes the vehicle's wheel to rotate, therebycausing the electromagnetic actuators to act as generators and to chargethe vehicle's batteries. The recharging device may be powered by, forexample, electricity or fuel.

In some devices, heat produced by the reciprocation of the coils 115 a,115 b may be reduced by spraying a liquid coolant, such as, for example,water, on the coils 115 a, 115 b. This may be accomplished by sprayingliquid through openings 146 in the magnets of the magnetic stators 125a, 125 b and onto the coils 115 a, 115 b as they pass by the openings146. The liquid coolant may be transported to the openings 146 throughchannels in the magnetic stator assembly 120. The sprayed liquid maythen be collected for reuse or may be allowed to convert to a gas and bevented from the rotary device.

FIGS. 2E-2H also illustrate components of an example rotary device inaction, but with a wheel 140 that is attached to the cam 105 through aplate, or similar structure (not shown). A white circle appears on thewheel 140 to show the wheels position at different points duringreciprocation of the electromagnetic actuators 110 a, 110 b. Asillustrated by the white circle in 2E-2H, the wheel 140 rotates alongwith the rotating cam 105.

FIG. 3A illustrates a rotary device similar to the device of FIGS.2A-2C, but with an additional cam 106 on the other side of the magneticstator assembly 120. Reciprocation of the coils 115 a, 115 b acts toalso drive the second cam 106 in rotary motion, and the second cam 106may be attached to the other side of a wheel using, for example, anothercircular plate. Also shown is that the magnetic stator assembly 120 ofthe example device may be in the shape of a long extended box-shapedcore of magnetically permeable material, with a magnetic stator 125 a,125 b at either end. In the example device, each magnetic stator 125 a,125 b includes magnets on all four sides of the magnetic stator assembly120. The box-shaped core, on which the magnetic stators 125 a, 125 b areaffixed in the example device, may act as a return path for the magneticflux of the magnetic stators 125 a, 125 b. Also shown in FIG. 3A is thatthe coils 115 a, 115 b of the electromagnetic actuators may have arectangular shaped cross-section and arranged to surround the magneticstators 125 a, 125 b. This arrangement allows for efficient utilizationof the electromagnetic forces between the coils 115 a, 115 b and themagnetic stators 125 a, 125 b.

FIG. 3B illustrates the rotary device of FIG. 3A, but with additionalmagnets 325 a, 325 b arranged outside of the coils 115 a, 115 b.According to the example device, each end of the magnetic statorassembly 120 includes an additional four magnet arrays, one on each sideof a rectangular cross-section coil 315 a, 315 b. The additional magnets325 a, 325 b enables the creation of more electromagnetic force. Alsoshown in FIG. 3B is an additional magnetic return path 320 for theadditional magnets 325 a, 325 b.

FIG. 4A illustrates a mount 145 to which the magnetic stator assembly120, including magnets and return paths, may be attached. The mount maybe part of, or further attached to, for example, a chassis of a vehicle(not shown). Specifically, the mount 145 includes outer and inner hubplates 445 a, 445 b, the latter of which may be bolted to the chassis ofa vehicle. Delivery of electrical current to the coils 115 a, 115 b maybe accomplished using electricity-conducting flexures (not shown in FIG.4A) that extend from the mount 145 to the coils 115 a, 115 b. Theflexures allow current to be delivered to the coils 115 a, 115 b even asthe coils reciprocate along the magnetic stator assembly 120. Thus, theflexures may electrically couple to an electrical supply (not shown inFIG. 4A), such as a battery, coupled to the mount or located in thechassis of a vehicle, the supply delivering electrical current to thecoils 115 a, 115 b.

FIG. 4B illustrates a simplified cross-section of an example rotarydevice attached to the chassis of a vehicle 405. FIG. 4B is similar toFIGS. 1D-1F, but with some components removed for clarity. The figuresshows a mount 145 coupled to the chassis of a vehicle 405 and a magneticstator assembly 120. Also shown are a cam 105, cam plate 170, wheel 140,bearing 150, and electromagnetic actuators 110 a, 110 b. Coupled to themount 145 is an electrical unit 410, which is used to deliverelectricity to the electromagnetic actuators 110 a, 110 b through a pairof flexures 415 a, 415 b. Also coupled to the mount 145 is a battery 420for storing electrical energy. Although the electrical unit 410 and thebattery 420 are shown as being coupled to the mount 145, the electricalunit 410, battery 420, or both may, instead, be coupled to the supportstructure 165 (FIG. 1D).

According to the example rotary device, the electrical unit 410 may becontrolled by a controller 430 on the chassis of the vehicle 405 andthrough a fiber-optic cable 435 running between the controller 430 andthe electrical unit 410. The example rotary device also includes abidirectional power line 440 connecting the electrical unit 410 and thebattery 420. During operation as a motor, power may flow from thebattery 420 to the electrical unit 410 and on to the electromagneticactuators 110 a, 110 b. During operation as a generator, power may flowfrom the electromagnetic actuators 110 a, 110 b to the electrical unit410 and on to the battery 420. The vehicle may also include a charger425 for charging the battery 420 using an external power source (notshown), such as an electrical outlet or gasoline engine in the case of ahybrid vehicle. During such charging, power flows from the externalpower source to the charger 425 and on to the battery 420 through line427, the electrical unit 410, and the bidirectional power line 440.Thus, the battery 420 may be charged by either an external power sourceor by the rotary device acting as a generator.

Through delivery of electricity to the electromagnetic actuators 110 a,110 b, the electrical unit 410 may control the reciprocation of thecoils. For example, when at speed, the electrical unit 410 may controlthe constant reciprocation of the coils. In vehicular embodiments, thecontroller 430 may be operated by a driver (not shown) of a vehicle and,in response to actions by the driver, the controller 430 may sendcommands to the electrical unit 410 to cause the rotary device toaccelerate, decelerate, or change direction, for example. In addition,the electrical unit 410 may be configured to provide an electricalcomponent to the electromagnetic actuators 110 a, 110 b to drive theircoils in the same direction, thereby creating a vertical translationalmovement of the wheel 140. Any translational movement of the wheel 140,caused by the rotary device or not, may be sensed by the electrical unit410. In some configurations, the electrical unit 410 may be configuredto absorb energy from the translational movement of the wheel by causingthe electromagnetic actuators 110 a, 110 b to act as electricalgenerators and dampers. This energy may be transferred to the battery420 for storage.

FIG. 5A illustrates a bearing support structure 165. A rotary bearing(not shown) that supports the cam plate and, thus, the wheel is mountedto a flange 585. The bearing support 165 and the electromagneticactuators 110 a, 110 b with coils 115 a, 115 b are kept in verticalalignment using a plurality of shafts 130 a-d. If the rotary device isemployed in the wheel of a vehicle, the support structure 165 allows themagnetic stator assembly 120, mount 145, and chassis of the vehicle (notshown) to remain suspended above the ground without electrical power. Inthe absence of the support structure 165, the magnetic stator assembly120, mount 145, and vehicle chassis may drop toward the ground whencurrent is not applied to the coils 115 a, 115 b. Thus, both the supportstructure 165 and the electromagnetic actuators 110 a, 110 b can providesuspension for the vehicle, but the electromagnetic actuators 110 a, 110b require electrical power to lift the magnetic stator assembly 120,mount 145, and vehicle chassis off the ground. The support structure165, on the other hand, may use fluid dampers (not shown) forsuspension.

The support structure 165 also enables the use of multiple flexures inseries for delivering electricity to the coils. For example, one set offlexures may run between the mount 145 and the support structure 165,and another set of flexures may run between the support structure 165and the coils 115 a, 115 b. Use of multiple flexures is advantageouswhen the bearing support 165 moves in a vertical direction. During suchvertical movement of the bearing support 165 and reciprocation of thecoils 115 a, 115 b, one set of flexures may flex with respect to thevertical movement of the bearing support 165, and the other set offlexures may flex with respect to the reciprocation of the coils 115 a,115 b. If only one set of flexures were used (e.g., connected directlybetween the mount 145 and the coils 115 a, 115 b), more flex would berequired upon vertical movement of the bearing support 165 andreciprocation of the coils 115 a, 115 b, possibly leading to increasedstress and wear on the flexures.

FIG. 5B illustrates the magnetic stator assembly 120, mount 145, andvehicle chassis as being raised with respect to the other components ofthe rotary device. This is accomplished either by adding an electricalcomponent to the coils 115 a, 115 b to cause both coils to move in thesame direction (e.g., in this case down relative to the stator assemblyand chassis) or by using the fluid dampers (not shown) of the supportstructure 165, as described below. The vertical movement of the coils115 a, 115 b may occur concurrently with, or apart from, opposed coilreciprocation. The effect that the vertical movement has on a vehicle,for example, is to raise or lower the vehicle's ride height or to act asa shock absorber (e.g., going over bumps). To raise a vehicle's rideheight, either the fluid dampers or the coils 115 a, 115 b may be usedto raise, and keep raised, the chassis of the vehicle with respect tothe wheels. To act as a shock absorber, either the fluid dampers or thecoils 115 a, 115 b may react to a bump in the road by allowing thewheels to quickly rise with respect to the chassis of the vehicle andthen return to their normal position. In addition, all four wheels of avehicle may be thrust rapidly downwards with respect to the chassis ofthe vehicle to cause the vehicle to jump off of the ground. Thus, therotary device may exhibit at least two degrees of movement: rotationalmovement with opposed reciprocation of the coils and linear movementwith movement of the coils in a common direction. These degrees ofmovement may be performed either separately or together.

FIG. 5C shows a horizontal cross-section through the device showing thesupport structure 165 as surrounding, but not coupled to, the mount 145.Also shown are a plurality of shafts 130 a-d coupled to the supportstructure to maintain alignment among the components of the rotarydevice. A plurality of fluid dampers 175 a-d, described below, are alsoshown.

FIG. 5D illustrates the side of an example rotary device including onepair of flexures 505 a, 505 b running between components 545 a, 545 b ofthe mount 145 and the support structure 165, and another pair offlexures 510 a, 510 b running between the support structure 165 and theelectromagnetic actuators 110 a, 110 b.

FIG. 6A illustrates a rotary bearing 150 used to couple the bearingsupport structure 165 with one of the cams 105. An inner race 650 a iscoupled to the bearing support 165 and an outer race 650 b couples awheel structure (not shown), such as a cam plate and, thus, to the cam105 and outer wheel rim. The wheel structure may be a plate, a pluralityof spokes, a lattice, or other appropriate structure as known in theart. The rotary bearing 150 is not coupled directly to the mount 145,but rather, in the example device, through a fluid damper. Anotherrotary bearing (not shown) may be used to couple the support structure165 with the other cam 105 on the other side of the rotary device.Because the rotary bearing 150 rotably couples the bearing supportstructure 165 with an outer wheel rim, the support structure 165 andwheel have the same vertical position with respect to each other.Because of its constant vertical position with respect to the wheel, theshafts 130 a-d may be fixed to the support structure 165, therebypreventing the shafts from coming into contact with the wheel.

FIG. 6B illustrates a wheel structure 605 coupling a cam 105 of anexample rotary device with a wheel rim 140 of a vehicle. As illustrated,the cam 105 is fixed to the wheel structure 605, and the wheel structure605 is fixed (e.g., using bolts) to the wheel 104 rim. Rotation of thecam 105, thus, causes rotation of the wheel structure 605 and the wheel104.

FIG. 7 shows a horizontal cross-section of an example rotary device. Thecross-section is cut through one of the electromagnetic actuators 155.Inside the electromagnetic actuator 155 is shown a coil 115 a and thecomponents of the magnetic stator assembly 120. According to theillustrated device, the magnetic stator assembly 120 includes an innermagnetic stator component 125 a, including a plurality of magnets, andan outer magnetic stator component 325 a, also including a plurality ofmagnets. The magnetic stator assembly 120 also includes an innermagnetic flux return path 725 a for the inner magnetic stator component125 a and includes an outer magnetic flux return path 735 a for theouter magnetic stator component 325 a. As described above, the innermagnetic stator component 125 a and inner magnetic flux return path 725a are located inside of the coil 115 a, and the outer magnetic statorcomponent 325 a and outer magnetic flux return path 735 a are locatedoutside of the coil 115 a. Also shown in the cross-section is thehousing of the electromagnetic actuator 155, which surrounds the coil115 a and magnetic stator assembly 120 and slides along the long axis ofthe magnetic stator assembly 120 by sliding along a plurality of shafts130 a-d. The housing of the electromagnetic actuator 155 may hold thecoil 115 a using, for example, four bolts that run through the cornersof the rectangular-shaped coil 115 a.

FIG. 8 shows another cross-section of the example rotary device, butfrom a top-down view. As in FIG. 7, the cross section shows a coil 115a, inner magnetic stator component 125 a, outer magnetic statorcomponent 325 a, inner magnetic flux return path 725 a, outer magneticflux return path 735 a, electromagnetic actuator housing 155 a, andshafts 130 a-d. The inner magnetic stator component 125 a and innermagnetic flux return path 725 a are mounted to an inner structure 820 ofan example magnetic stator assembly. As can be seen, a bolt may beinserted through bolt holes 815 at the corners of the coil 115 a to fixthe coil 115 a to the housing 155 a.

FIG. 9 illustrates an inner structure 820 of an example magnetic statorassembly. A mount 145 (FIG. 4A) may be attached at point 910 to, forexample, couple the structure 820 to the chassis of a vehicle. Channels905 a-d may be used to transport a cooling fluid within the magneticstator assembly to spray on the coils through the magnets.

FIG. 10 shows a cross-section of the example rotary device. Thecross-section is cut through the middle of the device and shows theinner structure 820 of the magnetic stator assembly, mount 145, innermagnetic flux return path 725 a, and outer magnetic flux return path 735a. The cross-section also shows a channel 1005 used to access the innerpart of the magnetic stator assembly for running wires or cooling fluid,for example.

FIG. 11 shows another cross-section of a rotary device as in FIG. 10,but at a point slight higher than the cross-section of FIG. 10. Inaddition to the channel 1005 for running wires or cooling lines, thecross-section shows channels 1105 a-d for inserting fasteners, such asscrews.

FIG. 12A shows a vertical cross-section of the example rotary device.The cross-section shows how the support structure illustrated in FIGS.5A and 5B may be slidably coupled to the magnetic stator assembly andthe mount 145 using additional shafts 1230 a, 1230 b and fluid dampers175 a, 175 b. As illustrated in FIG. 12A, the support structure 165 maybe coupled to the lower rod of a fluid damper 175 a. Specifically, aconnecting arm 1215 a pinned at point 1225 a to the lower end of the rod1220 a is joined to the support at point 1205. An upper rod of the fluiddamper 175 a may be connected to the mount 145 of the device, which maybe part of a vehicle's chassis. The mount 145 joins suspension arm 1240a at point 1210. The shaft 1230 a, fixed to the support 165, slidesthrough the suspension arm 1240 a at opposite ends. The upper rod of thedamper 175 a is pinned to the suspension arm 1240 a at point 1235 a.

The fluid dampers 175 a, 175 b may be a pneumatic suspension, such as apiston with opposing gas chambers. The pressure of the gas in eachchamber above and below the piston may also be dynamically adjusted toeither change the position of the magnetic stator assembly and the mount145 (e.g., move up or down) or to change the stiffness of the dampers175 a, 175 b. To change the position of the magnetic stator assembly andthe mount 145, pressure in the gas chambers may be adjusted so that thechambers have different pressures. For example, if the fluid dampers 175a, 175 b each include a top and bottom chamber, more pressure would beapplied to the top chamber to move the magnetic stator assembly and themount 145 in the upward direction, and more pressure would be applied tothe bottom chamber to move the magnetic stator assembly and the mount145 in the downward direction. To change the stiffness of the dampers175 a, 175 b, equal pressure may be added to or removed from the top andbottom chambers. If the rotary device is used in the wheel of a vehicle,changing the position of the magnetic stator assembly and the mount 145can change the ride height of the vehicle, and changing the stiffness ofthe dampers 175 a, 175 b can change the stiffness of the vehicle'ssuspension.

The cross-section of FIG. 12A also shows the inside of the magneticstator assembly. An example arrangement of the coil 115 b of anelectromagnetic actuator, inside magnetic stator component 125 b, andoutside magnetic stator component 325 b can be seen through thecross-section. Also visible is the magnetic flux return path 735 b forthe outside magnetic stator component 325 b.

FIGS. 12B-12D illustrate an example tunable pneumatic suspension. FIG.12B shows that the suspension 175 a includes a piston 1276 and opposedchambers 1277 a, 1277 b applying respective opposed pneumatic pressuresto opposite faces 1278 a, 1278 b of the piston 1276. The examplesuspension 175 a includes a top chamber 1277 a and a bottom chamber 1277b. Also shown is a pneumatic controller 1279 that independently controlsthe pneumatic pressures in the chambers 1277 a, 1277 b.

The pressures of the chambers 1277 a, 1277 b may be adjusted to changethe relative positions of the piston 1276 and the chambers 1277 a, 1277b by differing the pressures. For example, as shown in FIG. 12C, ahigher pressure in the bottom chamber 1277 b of the suspension 175 a, ascompared to the top chamber 1277 a, exerts more force on the bottom face1278 b of the piston 1276, causing the piston 1276 and the bottomchamber 1277 b to move away from each other. As shown in FIG. 12D, ahigher pressure in the top chamber 1277 a, as compared to the bottomchamber 1277 b, exerts more force on the top face 1278 a of the piston1276, causing the piston 1276 and the top chamber 1277 a to move to moveaway from each other. If the suspension 175 a is part of a vehicle, thismovement can change the ride height of the vehicle, the direction of thevehicle's movement depending on whether the chambers 1277 a, 1277 b orthe piston 1276 are coupled to the chassis of the vehicle. Either thechambers 1277 a, 1277 b or the piston 1276 may be grounded, while theother is coupled to the chassis of the vehicle.

In addition to changing the position of the piston 1276, the pressuresof the chambers 1277 a, 1277 b may be adjusted to change the stiffnessof the suspension 175 a by adding or removing equal pressures to or fromthe chambers 1277 a, 1277 b. Adding equal pressure to both chambers 1277a, 1277 b increases the stiffness of the suspension 175 a, and removingequal pressures from both chambers 1277 a, 1277 b decreases thestiffness of the suspension 175 a. If the suspension 175 a is part of avehicle, changing the stiffness of the suspension 175 a can change thestiffness of the vehicle's ride.

FIG. 13A illustrates an example rotary device incorporating many of theabove-described features. The rotary device includes, for example, a cam105, two opposed electromagnetic actuators (including an example housing155 a and coil 115 b), a magnetic stator assembly (including an exampleinner magnetic stator component 125 b, outer magnetic stator component325 b, and outer magnetic flux return path 735 b for the outer magneticstator component 325 b), mount 145, suspension arms 1240 a, 1240 b,followers 135 a-d, support structure 165, rotary bearing 150, shafts 130a, 130 b, 1230 a, 1230 b, and fluid dampers 175 a, 175 b.

FIG. 13B illustrates the rotary device of FIGS. 13A, but where the fluiddampers 175 a, 175 b have been used to raise the magnetic statorassembly and the mount 145 by, for example, applying more pressure to atop chamber within each of the fluid dampers 175 a, 175 b. Asillustrated in FIG. 13B, the fluid dampers 175 a, 175 b, suspension arms1240 a, 1240 b, magnetic stator assembly and the mount 145 are in avertically higher position than illustrated in FIG. 13A.

FIGS. 14A-14C illustrate the construction of an example coil from one ofthe electromagnetic actuators. Instead of being made from one continuouspiece of material, the coil may include multiple flat coil segmentsstacked together and electrically coupled in series. FIG. 14Aillustrates four coil segments that are combined into one coil 1400. Thecoil of a given electromagnetic actuator may include a number of suchcoils. FIG. 14B illustrates one of the coil segments 1401. FIG. 14Cillustrates an exploded view 1405 of the coil of FIG. 14A. Each segment1410 a-d of the example coil may be a flat, U-shaped piece of metalformed by, for example, a stamping or etching process. The segments 1410a-d may be assembled in the configuration shown in FIG. 14C to form afull coil.

FIG. 14C shows four U-shaped coil segments 1410 a-d that are stacked ontop of each other, where each segment is rotated 270 degrees (or 90degrees depending on the direction of rotation) with respect to the coilsegment it follows in the stack of coil segments. In stacking thesegments 1410 a-d in rotated positions, the segments 1410 a-d may bepositioned so that a starting end 1425 of an upper coil segment 1410 bin the stack interfaces a finishing end 1420 of an immediately lowercoil segment 1410 a in the stack. The coil including the four U-shapedcoil segments 1410 a-d, for example, loops around three times to finishat the same relative position (e.g., ends 1415 and 1450) that itstarted.

Electric current may flow through the coil, for example, from a startingend of a bottom-most coil segment in the stack to a finishing end of atop-most coil segment in the stack. In the example coil, when assembled,electrical current 1455 may flow through the coil, for example, from astarting point 1415 to an ending point 1450. The current 1415 may beginat point 1415 and flow counter-clockwise around segment 1410 a to point1420. At point 1420, the current continues to point 1425 as points 1420and 1425 are in electrical contact with each other once assembled, asshown, for example, in FIG. 14A. From point 1425, the current 1415 flowscounter-clockwise around segment 1410 b to point 1430, where the currentcontinues to point 1435 as described above. From point 1435, the current1415 flows counter-clockwise around segment 1410 c to point 1440, wherethe current continues to point 1445, and flows counter-clockwise aroundsegment 1410 d to point 1450. If combined with other segments, thecurrent may continue to flow from one segment to a subsequent segment ina longer coil. Overall, a method of manufacturing such an electric coilincludes fabricating the multiple flat coil segments, stacking themultiple coil segments together where each coil segment is rotated withrespect to the coil segment it follows, and fastening the coil segmentstogether to form the electric coil.

To prevent the electrical current from straying from the above-describedpath, each segment may be coated with an electrically-insulating layerof material, except for the surfaces between which the current is meantto propagate, such as the top surface of point 1420 and the bottomsurface of point 1425. Alternatively, instead of being coated, layers ofelectrically-insulating material may be inserted between the coilsegments. When the coil segments 1410 a-d are assembled in the formillustrated in FIG. 14A, fasteners, such as bolts, may be insertedthrough the openings shown at points 1415, 1420, 1425, 1430, 1435, 1440,1445, and 1450. The segments 1410 a-d may also be joined by soldering orbrazing in addition to, or instead of, preloading the mechanical andelectrical connections with fasteners. When the segments 1410 a-d areassembled, there may remain gaps between some of the above points. Toallow the fasteners to tightly secure the coil segments 1410 a-dtogether, electrically-insulating spacers may be inserted between thepoints to fill the gaps. For example, when the segments 1410 a-d areassembled, a gap may remain between points 1415 and 1450, and one ormore spacers may be inserted between points 1415 and 1450 to fill thegap. On the other hand, no gap should exist between points 1420 and1425. The fasteners may also be insulated using, for example, heatshrink tubing.

The coil segments 1410 a-d may be mechanically and electrically joinedtogether using bolts that pass through openings included in the segments1410 a-d, where the openings are positioned outside the coil path sothat a continuous, helical, flat coil may be formed. Fabricating coilsegments at a constant thickness may be simple and inexpensive, but, ata constant thickness, the coil segment connections may occur outside thecoil path so that intermediate segments do not overlap with theconnection points. The shape of the connection points 1415, 1420, 1425,1430, 1435, 1440, 1445, 1450 may be chosen so that there is adequatecontact area for a good mechanical connection that produces anacceptable contact resistance between the segments. The coil segmentsmay be electroplated, with gold or nickel for example, to further reducethe contact resistance.

The connection points 1415, 1420, 1425, 1430, 1435, 1440, 1445, 1450 maybe raised or lowered so that the coil path continues in a smooth manner,without any sudden ledges or stress points, and with the connectioncentered at the level of connection. For example, for the connectionbetween segments 1410 a and 1410 b, point 1420 may be lowered and point1425 may be raised, as illustrated in FIG. 14C. The amount that thepoints are raiser or lowered by may be one-half of the thickness of thesegments 1410 a-d. The overall helical path may be set by slightinclines, or a continuous incline, included in supporting structuresimmediately above and below the coil. The supporting structures may beclamped-down on the coil when the bolts are tightened, and can alsoinclude starting levels for the four bolts so that the coil may beformed with smooth transitions and minimal deformation in the segments1410 a-d when the bolts are tightened. A similar approach is possiblewhere three bolts are used and segments repeat more frequently, possiblyforming a triangular shaped coil. Use of a greater number of bolts isalso possible. The segments may also be fabricated so that a circularpath is formed, rather than a rectangular one.

Instead of including raised and lowered sections in the coil segments1410 a-d, the connection points 1415, 1420, 1425, 1430, 1435, 1440,1445, 1450 may be of half-thickness, where two segments join together toyield the coil path thickness, and the path would continue smoothly.This type of connection may overlap with intermediate segments to alarger degree. Additionally, in some devices, added stress anddeformation caused by not raising and lowering the connection points1415, 1420, 1425, 1430, 1435, 1440, 1445, 1450 in the segments 1410 a-dmay be acceptable, and the tensioning in the bolts may be used to givethe segments 1410 a-d their final shape.

FIG. 15 illustrates another example rotary device 1500 inside a wheel.As with the devices described above, the device 1500 may be attached tothe chassis of a vehicle. The device 1500 includes a cam 1505, twoopposed electromagnetic actuators 1510 a, 1510 b, a magnetic statorassembly 1520 (including magnetic stators 1515 a, 1515 b), a supportstructure 1525, and fluid dampers 1530 a, 1530 b. The rotary devicedepicted inside the wheel may be attached to the wheel via the cam 1505as described below.

FIG. 16A illustrates the example rotary device 1500 with the tire of thewheel, and some other components, removed. The device 1500 is similar tothe devices described above, but includes a central disc 1635 sandwichedbetween to pairs of electromagnetic actuators 1510 a, 1510 b, 1610 a,1610 b and two magnetic stator assemblies 1520, 1620. Each of themagnetic stator assemblies 1520, 1620 includes two magnetic stators 1515a, 1515 b, 1615 a, 1615 b, which include magnetic flux return paths 1640a-d and magnets (e.g., 1630 a, 1630 b). The housings surrounding thecoils of the electromagnetic actuators 1510 a, 1510 b, 1610 a, 1610 bare not shown. Each coil reciprocates along four arrays of magnets,which, as described above, may include multiple magnets. Two of themagnet arrays are located inside the coil (e.g., inner magnetic statorcomponent 1630 b) and two are located outside the coil (e.g., outermagnetic stator component 1630 a). Each set of magnets are mounted to amagnetic flux return path 1640 a-d.

The disc 1635 includes two cams, one on either side of the disc 1635.Each cam of the example device is in the form of a grove that includesan inner surface 1605 a and an outer surface 1605 b. Coupled toelectromagnetic actuators 1510 a and 1510 b are two pairs of followers1625 a, 1625 b, the different followers of each pair interfacing with arespective surface 1605 a, 1605 b of the cam. Electromagnetic actuators1610 a and 1610 b are similarly coupled to followers. As the coils movetowards each other, one of the followers of each electromagneticactuator 1510 a, 1510 b exerts force on the inner surface 1605 a of thecam. As the coils move away from each other, the other follower exertsforce on the outer surface 1605 b of the cam.

FIG. 16B illustrates a different view of the example rotary device 1500.It should be apparent that each pair of electromagnetic actuators (pair1510 a, 1510 b and pair 1610 a, 1610 b) are at different phases ofreciprocation. This is because, in the example device, the cams oneither side of the disc 1635 are rotationally offset from each other by,for example, forty-five degrees. This helps to prevent the actuatorsfrom stopping at a point on the cams from which it would be difficult toagain start. Thus, if one pair of actuators stops on a “dead-spot” ofits respective cam, the other pair of actuators would not be at adead-spot. Alternatively, if the cams were not offset from each other,or if only one cam were used, a controller may control the rotation ofthe cam so that the actuators do not stop on a dead spot. FIG. 16B alsoillustrates an arrangement of the coils and magnetic stator components.For example, magnetic stators components 1630 b and 1630 c are locatedinside the coil of actuator 1610 a, and magnetic stators components 1630a and 1630 d are located outside the coil.

FIG. 16C illustrates two rotationally offset cams 1505, 1606. The cams1505, 1606 may be part of or mounted on a disc 1635. One cam 1505 may beon one side of the disc 1635, and the other cam 1606 may be on theopposite side, as indicated by the dashed line. In some devices the cammay be offset by forty-five degrees, for example. The cams 1505, 1606may have any even number of lobes. Cams having two lobes, for example,may be offset by forty-five degrees. Cams having four lobes, forexample, may be offset by twenty-two and a half degrees.

FIG. 16D illustrates a vertical cross-section of a disc 1635 with tworotationally offset cams, each having in inner surface 1605 a, 1605 cand an outer surface 1605 b, 1605 d. Due to the offset, the innersurfaces 1605 a, 1605 c are not in line with each other. Likewise, theouter surfaces 1605 b, 1605 d are also not in line with each other.

FIG. 16E illustrates that the inner and outer surfaces 1605 a, 1605 b ofa cam may be shaped in a complex pattern, such as, for example, a shapehaving an even number of lobes. As noted above, the sides of each lobemay be shaped in the form of a sine wave or portions of an Archimedesspiral, for example. The inner and outer surfaces 1605 a, 1605 billustrated in FIG. 16E each have four lobes.

FIG. 17A illustrates how the disc 1635 of the example rotary device maybe coupled to the rim 1705 of a wheel. The rim 1705 may consist of onepiece to which the disc 1635 may be affixed using fasteners, such asbolts, along an inner ring 1715. Alternatively, the rim 1705 may includetwo parts 1710 a, 1710 b that bolt together along ring 1715. Whenfastened together, the two parts 1710 a, 1710 b form a full rim 1705with inner ring 1715. A tire may then be mounted to the rim 1705. FIG.17B shows how the disc 1635 may be fastened to the inner ring 1715 ofthe disc 1635.

FIG. 18 illustrates two support structures 1525, 1825 couplingrespective magnetic stator assemblies 1520, 1620 with electromagneticactuators 1510 a, 1510 b, 1610 a, 1610 b through a plurality of shaftsand fluid dampers 1530 a, 1530 b, 1830 a. Support structure 1525 isslidably coupled to magnetic stator assembly 1520 using fluid dampers1530 a, 1530 b. Fluid damper 1530 a may be coupled to the supportstructure 1525, for example, at point 1810 and coupled to magneticstator assembly 1820 a at point 1805. Likewise, support structure 1825is slidably coupled to magnetic stator assembly 1620 using fluid damper1830 a and a corresponding fluid damper (now shown) on the far side ofthe device.

FIGS. 19A-19C illustrate an example arrangement of the components of amagnetic stator assembly. Referring to FIG. 19A, magnet array 1910 a isan outer magnet array and magnet array 1910 b is an inner magnet array.The overall magnetic flux return path 1640 a supports the magnet arrays.The particular geometric shape of the example return path 1640 a allowsthe return path 1640 a to be formed using a cost-effective extrusionprocess. Specifically, four flux paths may be joined together at acenter junction and two end junctions, and many such structures may becut from a single extrusion. Also illustrated is a base structure 1920 aon which the magnetic stator components may be mounted.

FIG. 19B illustrates a component 1905 used to deliver liquid coolant tothe magnets, which may be sprayed onto the coils as they pass by themagnets. Liquid coolant may be transported from the base structure 1920a to the magnet arrays 1910 a, 1910 b through a component 1905 that isfastened along the edge of the return path 1640 a. The liquid may flowthrough an opening 1915 in the base structure 1920 a, through a channel1917 of the component 1905, and into a chamber 1925 located in a gapformed by parts of the return path 1640 a. From inside the chamber 1925,the liquid coolant may be directed through openings (e.g., holes) in themagnet arrays 1910 a, 1910 b and sprayed onto the coils as theyreciprocate by the openings.

FIG. 19C illustrates four magnetic stators that are coupled to a centralmount 1945. If the rotary device is employed in the wheel of a vehicle,for example, the mount 1945 may be coupled to the chassis of thevehicle.

FIGS. 20A-20G illustrate the construction of an example coil from one ofthe electromagnetic actuators. FIG. 20A shows an entire coil 2000 froman electromagnetic actuator. It should noted that the coil 2000 mayconsist of many smaller coils. FIG. 20B illustrates four coil segmentsthat are combined into one coil 2005. A number of such segments may becombined to form the larger coil 2000 of FIG. 20A. FIG. 20C is anexploded view 2010 of the coil 2005 of FIG. 20B. Each segment 2015,2020, 2025, 2030 of the example coil may be a flat piece of metal formedby, for example, a stamping or etching process. The segments 2015, 2020,2025, 2030 may be assembled in the configuration shown in FIG. 20C toform a full coil. When assembled, electrical current 2075 may flowthrough the coil, for example, from starting point 2035 to ending point2070. For example, the current 2075 may begin at point 2035 and flowcounter-clockwise around segment 2015 to point 2040. At point 2040, thecurrent continues to point 2045 as points 2040 and 2045 are inelectrical contact with each other when the segments are combined. Frompoint 2045, the current 2075 flows counter-clockwise around segment 2020to point 2050, where the current continues to point 2055 as describedabove. From point 2055, the current 2075 flows counter-clockwise aroundsegment 2025 to point 2060, where the current continues to point 2065,and flows counter-clockwise around segment 2030 to point 2070.

As described above, to prevent the electrical current from straying fromthe above-described path, each segment may be coated with anelectrically-insulating layer of material, except for the surfacesbetween which the current is meant to propagate, such as the top surfaceof point 2040 and the bottom surface of point 2045. When the coilsegments are assembled in the form illustrated in FIG. 20B, fasteners,such as bolts, may be inserted through the openings of the segments.When the segments are assembled, there may remain gaps between some ofthe above points. To allow the fasteners to tightly secure the segmentstogether, electrically-insulating spacers may be inserted between thepoints to fill the gaps.

FIG. 20D shows one coil segment 2015. FIG. 20E shows a second coilsegment 2020 stacked on top of segment 2015. FIG. 20E shows a third coilsegment 2025 stacked on top of segments 2015 and 2020, and FIG. 20Gshows a fourth coil segment 2030 stacked on top of segments 2015, 2020,and 2025, resulting in a full coil as illustrated in FIG. 20B.

FIG. 21A illustrates a side view of two rotary devices with respectivewheels 2105 a, 2105 b. FIG. 21B illustrates a top view of the same twodevices and wheels 2105 a, 2105 b. The two devices are used in tandemand may be used in vehicular applications. For example, a vehicle mayinclude four pairs of devices, one pair at each corner of the vehicle.Each device includes a magnetic stator assembly, opposed coils, andlinear-to-rotary converter (hidden from view). The devices are coupledto respective wheels 2105 a, 2105 b and are held together with a centralmounting structure 145. The mounting structure 145 may include, or becoupled to, a vertical shaft 2110 for coupling to the chassis of avehicle. The shaft 2110 may allow rotation of the two wheels 2105 a,2105 b relative to the chassis of the vehicle and about the shaft 2110.

FIGS. 22A-22C illustrate example rotations of the wheels 2105 a, 2105 b.FIG. 22A shows that the rotary devices may create propulsion for thevehicle by causing both wheels 2105 a, 2105 b to rotate in the samedirection. FIG. 22B shows that the rotary devices may cause the twowheels to turn with respect to the vehicle by rotating the wheels 2105a, 2105 b at differential rates. The difference in wheel rotation ratescreates propulsion for the vehicle and causes the vehicle to move alonga curved path. FIG. 22C shows that the rotary devices may cause the twowheels to turn with respect to the vehicle by rotating the wheels 2105a, 2105 b in opposite directions when the vehicle is not in motion.

FIGS. 23A and 23B illustrate example vertical movement of the wheels2105 a, 2105 b. FIG. 23A shows that one of the devices may cause itsrespective wheel 2105 b move in a vertical direction off of the ground.The wheel 2105 b may also be rapidly shook in the vertical direction toremove liquid from the surface of the wheel 1205 b. Additionally, bothwheels 2105 a, 2105 b may move up or down together to lower or raise theride height of the vehicle. The two wheels 2105 a, 2105 b may even bethrust downward with sufficient force to cause the vehicle to jump. FIG.23B shows that the shaft 2110 may be coupled to the chassis of thevehicle so as to allow for angular movement of the shaft 2110 relativeto the chassis by, for example, using a pivot 2305 or similar componentto couple the shaft 2110 with the chassis. In this configuration,different vertical movements of the two wheels 2105 a, 2105 b causes thewheels 2105 a, 2105 b to tilt, or camber. For example, one wheel 2105 amay move downward and the other wheel 2105 b may move upward, causingthe wheels 2105 a, 2105 b, as well as the mount 145 and shaft 2110 totilt. Alternatively, a pivot, or similar component, may be used tocouple the shaft 2110 with the mount 145, causing the wheels 2105 a,2105 b and the mount 145 to tilt, but not the shaft 2110.

FIGS. 24A-24F illustrate a top view of a vehicle 2405 having four pairsof rotary devices with respective pairs of wheels 2410 a-d. FIG. 24Ashows the vehicle 2405 with four pairs of rotary devices and respectivewheels 2410 a-d, one pair at each corner of the vehicle 2405. Thevehicle may also be configured with different wheel arrangements, suchas two pairs of rotary devices and respective wheels at the frontcorners of the vehicle. In such an arrangement, the wheels at the rearcorners of the vehicle may be conventional vehicle wheels. As shown inFIG. 24A, all of the wheel pairs 2410 a-d may be oriented in the forwarddirection to provide forward propulsion for the vehicle. FIG. 24B showsthat the two front pairs of wheels 2410 a, 2410 b may be turned to theright, for example, to cause the moving vehicle 2405 to turn to theright. FIG. 24C shows that the rear pairs of wheels 2410 c, 2410 d maybe turned in a complimentary direction, for example, to the left, toimprove the turning radius of the vehicle 2405. FIG. 24D shows that eachof the wheel pairs 2410 a-d may be oriented in a direction that istangential to a circular path to cause the vehicle 2405 to rotate aboutits center. FIG. 24E shows that each of the wheel pairs 2410 a-d may beoriented in the same direction, other than the forward direction, tocause the vehicle 2405 to move, for example, diagonally or sideways.FIG. 24F shows that each of the wheel pairs 2410 a-d may be pointedtoward, or away from, the center of the vehicle to prevent any movementof the vehicle, obviating the need for a parking brake. The independentmovements of each wheel may be controlled by a respective electricalunit 410 (FIG. 4B) and all movements may be coordinated by a centralcontroller 430 (FIG. 4B) in communication with the electrical units.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. For example, in addition to beingused in a motor vehicle, the disclosed devices may also be used intrains, planes, robots, and force-reflecting human interfaces.

What is claimed is:
 1. A rotary drive comprising: a rotatable memberthat defines a rotational axis; a first linear actuator comprising afirst mounted member having a first linear axis that is orientedradially relative to the rotational axis and a first moving member thatmoves in a linear direction along the first linear axis and relative tothe first mounted member when a drive signal is applied to the firstlinear actuator; a second linear actuator comprising a second mountedmember having a second linear axis that is oriented radially relative tothe rotational axis and a second moving member that moves in a lineardirection along the second linear axis and relative to the secondmounted member of the second linear actuator when a drive signal isapplied to the second linear actuator; a mounting structure with thefirst and second mounted members of the first and second linearactuators mounted thereon; a converter assembly to which the rotatablemember and the moving members of the first and second linear actuatorsare coupled and which, during operation, (a) converts a first type ofmovement of the moving members of the first and second linear actuatorsto rotary movement of the rotatable member about the rotational axis;and (b) in response to a second type of movement of the moving membersof the first and second linear actuators, enables the rotatable memberand the mounting structure to move relative to each other in a directionthat is orthogonal to the rotational axis.
 2. The rotary drive of claim1, wherein the mounted member of the first linear actuator comprises afirst magnetic stator, said first magnetic stator including one or moremagnets generating magnetic fields and the moving member of the firstlinear actuator comprises a first coil circumscribing the first magneticstator and arranged to reciprocate within the magnetic fields generatedby the first magnetic stator, and wherein the mounted member of thesecond linear actuator comprises a second magnetic stator, said secondmagnetic stator including one or more magnets generating magnetic fieldsand the moving member of the second linear actuator comprises a secondcoil circumscribing the second magnetic stator and arranged toreciprocate within the magnetic fields generated by the second magneticstator.
 3. The rotary drive of claim 2 wherein the converter assemblycomprises a linear-to-rotary converter coupled between the first andsecond moving members and the rotatable member.
 4. The rotary drive ofclaim 2, wherein the converter assembly comprises: (a) alinear-to-rotary converter to which the rotatable member and the movingmembers of the first and second linear actuators are coupled and whichduring operation converts the first type of movement of the movingmembers of the first and second linear actuators to rotary movement ofthe rotatable member about the rotational axis; and (b) a bearingassembly supporting the rotatable member and enabling the rotatablemember in response to the second type of movement of the moving membersof the first and second linear actuators to move relative to themounting structure and in the direction that is orthogonal to therotational axis.
 5. The rotary drive of claim 4, wherein the bearingassembly comprises a bearing support on which the rotatable member ismounted for rotation and a plurality of shafts that enable relativemovement between the bearing support and the mounting structure in thedirection orthogonal to the rotational axis in response to the secondtype of movement of the moving members of the first and second linearactuators.
 6. The rotary drive of claim 4, wherein the bearing assemblycomprises a plurality of shafts and a plurality of linear bearingsmovably supporting the moving members of the first and second linearactuators on the plurality of shafts.
 7. The rotary drive of claim 2,further comprising a wheel rim for supporting a tire, said wheel rimmounted on the rotatable member.
 8. The rotary drive of claim 7, whereinthe first and second linear actuators, the converter assembly, and thesupport structure are located within the boundaries of the wheel rim. 9.The rotary drive of claim 2, wherein the first coil circumscribes atleast some of the one or more magnets of the first magnetic stator. 10.The rotary drive of claim 2, wherein the second coil circumscribes atleast some of the one or more magnets of the second magnetic stator. 11.The rotary drive of claim 2, wherein the first coil and the second coilare opposed to each other relative to the rotational axis.
 12. Therotary drive of claim 2, wherein the first and second axes are parallelto each other.
 13. The rotary drive of claim 2, wherein the first andsecond axes are collinear.
 14. The rotary drive of claim 2, wherein theconverter assembly comprises a cam.
 15. The rotary drive of claim 14,wherein the converter assembly further comprises first and secondlinkages coupling the first and second coils, respectively, to the cam.16. The rotary drive of claim 15, wherein the first and second linkagescomprise cam followers which engage with the cam.
 17. The rotary driveof claim 2, wherein the first type of movement involves the first andsecond coils moving in opposite directions to each other.
 18. The rotarydrive of claim 2, wherein the second type of movement involves the firstand second coils moving in a common direction relative to each other.19. The rotary drive of claim 2, further comprising liquid injectionports arranged to flow coolant onto the first and second coils as thecoils reciprocate within the magnetic fields during operation.
 20. Therotary drive of claim 19, wherein the liquid injection ports arearranged in the first and second magnetic stators.
 21. The rotary driveof claim 20, wherein and liquid injection ports are openings in themagnets of the first and second magnetic stators.
 22. The rotary driveof claim 2, further comprising a rotary bearing with the rotatablemember rotatably supported on the support structure by the rotarybearing.